Solid electrolyte

ABSTRACT

A solid electrolyte glass at least including: at least one alkali metal element; 
     a phosphorus (P) element; a sulfur (S) element; and one or more halogen elements selected from I, Cl, Br and F; wherein the solid electrolyte glass has two exothermic peaks that are separated from each other in a temperature range of 150° C. to 350° C. as determined by differential scanning calorimetry (in a dry nitrogen atmosphere at a temperature-elevating speed of 10° C./min from 20 to 600° C.).

TECHNICAL FIELD

The invention relates to a solid electrolyte.

BACKGROUND ART

Recently, there is an increasing demand for a lithium ion secondarybattery, which is used in PDA, a portable electronic device, a home-usecompact power storage facility, an auto-bicycle powered by a motor, anelectric vehicle, a hybrid electric vehicle or the like.

In the above-mentioned lithium-ion batteries, an organic electrolyte isused as an electrolyte. Although an organic electrolyte has a high ionicconductivity, occurrence of leakage, ignition or the like to threatenthe safety is concerned due to its nature of being liquid and flammable.

As a method for ensuring safety of a lithium ion secondary battery, anall-solid secondary battery in which an inorganic solid electrolyte isused instead of an organic electrolyte has been studied. However, ingeneral, an inorganic solid electrolyte has a small ionic conductivityas compared with an organic electrolyte, and hence, practicalapplication of an all-solid secondary battery was difficult.

As an inorganic solid electrolyte, a lithium ion-conductive ceramicsbased on Li₃N has been reported. However, due to a low decompositionvoltage, this ceramics could not be used in an all-solid secondarybattery that is operated at a voltage of 3V or higher.

Non-Patent Document 1 discloses a solid electrolyte formed of asulfide-based crystallized glass having a high lithium ion conductivity.However, the electrolyte disclosed in Non-Patent Document 1 isindustrially disadvantageous since it requires a large amount ofexpensive germanium.

Patent Document 1 discloses that, in a glass sulfide-based solidelectrolyte material that contains an ion conductor having an orthocomposition and LiI and has a glass transition temperature, the ionicconductivity is increased to 1.0×10⁻³ S/cm.

In addition to those mentioned above, in the field of an all-solidbattery, a sulfide-based solid electrolyte material has conventionallybeen used. For example, Patent Document 2 reports that glass ceramicselectrolyte particles having a high ionic conductivity (˜2×10⁻³ S/cm)can be obtained by mixing Li₂S and P₂S₅ at a specific molar ratio (68:32to 73:27) and subjecting the mixture to mechanical milling, followed bya heat treatment. However, this material has a high reactivity and henceusage environment thereof is restricted.

Several methods have been proposed as a technology for suppressing thisreactivity. The technology disclosed in Patent Document 3 has a problemthat, while the reactivity is lowered, the ionic conductivity issignificantly lowered.

Patent Document 1 discloses a solid electrolyte composed ofsulfide-based crystallized glass having a high lithium ion conductivity.The electrolyte disclosed in Non-Patent Document 1 is industriallydisadvantageous since a large amount of expensive lithium is required.

Further, Non-Patent Document 1 as mentioned above discloses that theionic conductivity of the electrolyte is improved to 1.0×10⁻³ S/cm byaddition of lithium iodide. However, further improvement in ionicconductivity has been required.

RELATED ART DOCUMENTS Patent Documents

-   Patent Document 1: JP-A-2012-48973-   Patent Document 2: JP-A-2005-228570-   Patent Document 3: JP-A-2010-199033

Non-Patent Document

-   Non-Patent Document 1: N. Kamaya, et al. Nature Materials 10, 682    (2011)

SUMMARY OF THE INVENTION

An object of the invention is to provide a solid electrolyte having ahigher ionic conductivity that is suited for use in an all-solidsecondary battery.

According to the invention, the following solid electrolytes or the likeare provided.

1. A solid electrolyte glass comprising:

at least one alkali metal element;

a phosphorus (P) element;

a sulfur (S) element; and

one or more halogen elements selected from I, Cl, Br and F;

wherein the solid electrolyte glass has two exothermic peaks that areseparated from each other in a temperature range of 150° C. to 350° C.as determined by differential scanning calorimetric measurement (in adry nitrogen atmosphere at a temperature-elevating speed of 10° C./minfrom 20 to 600° C.).

2. The solid electrolyte glass according to 1, wherein the difference intemperature between the peak top positions of the two exothermic peaksis 20° C. or higher and 150° C. or lower.3. The solid electrolyte glass according to 1, wherein the difference intemperature between the peak top positions of the two exothermic peaksis 30° C. or higher and 130° C. or lower.4. The solid electrolyte glass according to any one of 1 to 3, that hasa composition represented by the following formula (1):

L_(a)M_(b)P_(c)S_(d)X_(e)  (1)

wherein in the formula, L is an alkali metal; M is one or more elementsselected from B, Al, Si, Ge, As, Se, Sn, Sb, Te, Pb and Bi; and X is oneor more halogen elements selected from I, Cl, Br and F; and

a to e independently satisfy the following formula:

0<a≦12, 0≦b≦0.2, c=1, 0<d≦9 and 0<e≦9.

5. A method for producing the solid electrolyte glass according to anyone of 1 to 4, wherein the following (1-A), (1-B) and (1-C) are used asraw materials:

(1-A) alkali metal sulfide

(1-B) compound represented by M′_(m)S_(n)

(1-C) compound represented by M″_(w)X_(y)

wherein in the formula, M′ is B, Al, Si, P or Ge; M″ is Li, Na, B, Al,Si, P, S, Ge, As, Se, Sn, Sb, Te, Pb or Bi; X is F, Cl, Br or I; w is aninteger of 1 to 2; and m, n and y are an integer of 1 to 10.

6. The method for producing the solid electrolyte glass according to 5,comprising a step of reacting the raw materials (1-A) and (1-B), andadding the raw material (1-C) to allow it to react with a reactionproduct of the raw materials (1-A) and (1-B).7. The method for producing the solid electrolyte glass according to 5or 6, comprising a step of reacting in an atmosphere having an oxygenconcentration of 19 to 21%.8. The method for producing the solid electrolyte glass according to anyone of 5 to 7, wherein 1 to 5 mol % of Li₂SO₃ is further added as acomponent (1-D).9. A solid electrolyte glass that is obtained by the method forproducing the solid electrolyte glass according to any one of 5 to 8.10. A solid electrolyte glass ceramic obtained by subjecting the solidelectrolyte glass according to any one of 1 to 5 and 9 to a heattreatment at a temperature between the two exothermic peaks.11. The solid electrolyte glass ceramic according to 10 that has anionic conductivity of 1×10⁻³ S/cm or more.12. A positive electrode mix that comprises at least one of the solidelectrolyte glass according to any one of 1 to 5 and 9 and the solidelectrolyte glass ceramic according to 10 or 11, and a positiveelectrode active material.13. A negative electrode mix that comprises at least one of the solidelectrolyte glass according to any one of 1 to 5 and 9 and the solidelectrolyte glass ceramic according to 10 or 11, and a negativeelectrode active material.14. An all-solid battery that comprises a solid electrolyte layercontaining at least one of the solid electrolyte glass according to anyone of 1 to 5 and 9 and the solid electrolyte glass ceramic according to10 or 11.15. An all-solid battery comprising a positive electrode layercomprising the positive electrode mix according to 12.16. An all-solid battery comprising with a negative electrode layercomprising the negative electrode mix according to 13.17. The all-solid battery according to any one of 14 to 16 that isobtained by heat treating the solid electrolyte glass contained in thesolid electrolyte layer, the positive electrode mix or the negativeelectrode mix at a temperature between exothermic peak temperatures ofthe two exothermic peaks that are separated from each other in atemperature range of 150° C. to 350° C. as determined by differentialscanning calorimetric measurement (in a dry nitrogen atmosphere at atemperature-elevating speed of 10° C./min and from 20 to 600° C.).

As a result of intensive studies, the inventors of the invention havefound that, a solid electrolyte having a prescribed amount or larger ofa specific crystal structure formed by a lithium element, a phosphoruselement, a sulfur element and a halogen element that constitute a solidelectrolyte has excellent lithium ionic conductivity. The invention hasbeen completed based on this finding.

According to the invention, the following solid electrolyte or the likeare provided.

1. A solid electrolyte comprising a lithium (Li) element, a phosphorus(P) element, a sulfur (S) element and a halogen element, wherein

the solid electrolyte has peaks derived from a crystal at 92.5±0.6 ppm,87.4±0.6 ppm, and 76.9±0.5 ppm in the solid ³¹PNMR spectrum, and

the ratio (x_(c)) of the crystal relative to the entire solidelectrolyte is 60 mol % to 100 mol %.

2. The solid electrolyte according to 1 that has a compositionrepresented by the following formula (1):

Li_(a)M_(b)P_(c)S_(d)X_(e)  (1)

wherein in the formula, M is B, Al, Si, Ge, As, Se, Sn, Sb, Te, Pb orBi, or a combination thereof, and X is I, Cl, Br or F, or a combinationthereof, and a toe satisfy 0<a≦12, 0≦b≦0.2, c=1, 0<d≦9 and 0<e≦9.

3. The solid electrolyte according to 1 or 2, wherein the halogenelement or the X is bromine (Br).4. The solid electrolyte according to any one of 1 to 3, wherein 98 at %of the constituting elements are a lithium (Li) element, a phosphorus(P) element, a sulfur (S) element and a halogen element.5. A method for producing a solid electrolyte wherein sulfide glass thatcomprises a lithium (Li) element, a phosphorus (P) element, a sulfur (S)element and a halogen element and two crystallization peak temperaturesare observed by a thermo-physical property measurement is subjected to aheat treatment at a temperature that is equal to or higher than a firstcrystallization peak temperature Tc1 on the low-temperature side and isequal to or lower than a second crystallization peak temperature Tc2 onthe high-temperature side among the two crystallization peaktemperatures.6. The method for producing a solid electrolyte according to 5, whereinthe heat treatment is conducted at a temperature that is equal to orhigher than the first crystallization peak temperature Tc1 and atemperature that is equal to or lower than an intermediate temperaturebetween the second crystallization peak temperature Tc2 on the hightemperature side and the Tc1.7. The production method according to 5 or 6, wherein the sulfide glassis produced by using Li₂S and P₂S₅ at a molar ratio of Li₂S:P₂S₅=70:30to 80:20.8. A solid electrolyte that is produced by the production methodaccording to any one of 5 to 7.9. A mix that comprises the solid electrode according to any one of 1 to4 and 8 and an electrode material.10. A mix that is produced from the solid electrode according to any oneof 1 to 4 and 8 and an electrode material.11. An electrode that comprises the solid electrolyte according to anyone of 1 to 4 and 8.12. An electrode that is produced from the solid electrolyte accordingto any one of 1 to 4 and 8.13. An electrolyte layer that comprises the solid electrolyte accordingto any one of 1 to 4 and 8.14. An electrolyte layer that is produced from the solid electrolyteaccording to any one of 1 to 4 and 8.15. A lithium ion battery that comprises the mix according to 9 or 10 orthe electrolyte layer according to 13 or 14 in one or more of theelectrolyte layer, a positive electrode and a negative electrode.

According to the invention, a solid electrolyte having a high ionicconductivity can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the results of a differentialthermo-gravimetric measurement of the solid electrolyte glass and thesolid electrolyte glass ceramic synthesized in Example 1;

FIG. 2 is a view showing the results of a differentialthermo-gravimetric measurement of the solid electrolyte glassessynthesized in Examples 1 to 3 and Comparative Examples 1 to 3;

FIG. 3 is a schematic view of an apparatus for producing the solidelectrolyte glass used in Example 9;

FIG. 4 is a solid ³¹PNMR spectrum having peaks only at positions of76.9±0.5 ppm, 86.4±0.5 ppm, 87.4±0.6 ppm. 92.5±0.6 ppm and 106.6±0.5 ppmexemplified in the Examples and the Comparative Examples in order toobtain the crystallization degree x_(c); and

FIG. 5 is an example of the spectra obtained by separating the spectrumshown in FIG. 4 into Gaussian curves.

MODE FOR CARRYING OUT THE INVENTION

Hereinbelow, an explanation will be made on a first aspect of theinvention.

A. Solid Electrolyte Glass

The solid electrolyte glass according to the first aspect of theinvention (hereinafter, often simply referred to as a “first solidelectrolyte glass”) is sulfide-based glass that is a precursor of asolid electrolyte glass ceramic mentioned later and at least contains atleast one alkali metal element, a phosphorus (P) element, a sulfur (S)element and one or more halogen elements selected from I, Cl, Br and F.

The solid electrolyte glass is characterized in that it has twoexothermic peaks that are separated from each other in a temperaturerange of 150° C. to 350° C. in a differential scanning calorimetricmeasurement.

Here, the differential scanning calorimetric measurement is conducted ina dry nitrogen atmosphere at a temperature-elevation speed of 10° C./minfrom 20 to 600° C. For example, it can be measured by using adifferential thermo-gravimetric measurement apparatus (TGA/DSC1manufactured by Mettler-Toledo International Inc.) or a differentialscanning calorimetric measurement apparatus (Diamond DSC manufactured byPerkinElmer Co., Ltd.) and by using about 20 mg of the solidelectrolyte.

The “two exothermic peaks that are separated from each other” means thatthe two peaks that do not overlap, or if overlapped, between these twopeaks, there is a region that is 20% or less of the maximum value(height) of each peak.

The height of the peak is a height based on a base line. The base lineis a line obtained by approximating a range of 75 to 150° C. to astraight line, followed by extrapolation. However, if a peak accompaniedby crystallization or bending by glass transition appears at 75 to 150°C., other ranges are approximated to a straight line, followed byextrapolation, and this line is used as the base line.

The first aspect of the invention has been completed based on a findingthat, when sulfide-based glass having two exothermic peaks that areseparated from each other is heated at a temperature between the peaksto obtain glass ceramic, the ionic conductivity of the glass ceramic isimproved.

For example, as a result of a thermal analysis of the electrolyte ofPatent Document 1, only one exothermic peak is present in theabove-mentioned temperature range. When only one exothermic peak ispresent as in this document, or, as in the Comparative Examplesmentioned later, two exothermic peaks are present but they areoverlapped, if the sulfide glass is allowed to be glass ceramic at atemperature between the peaks or a temperature around the peak, theionic conductivity of the obtained glass ceramic is lower than the solidelectrolyte ceramic according to the first aspect of the invention.

In glass ceramic, in order to increase the ionic conductivity, it iseffective to conduct a heat treatment such that a metastable phase isgenerated. However, if only one exothermic peak is present or twoexothermic peaks are overlapped, it is difficult to allow a metastablephase to be generated mainly.

In the first solid electrolyte glass of the invention, since it ispossible to retain for a prescribed period of time between the twoexothermic peaks (i.e. a temperature of from the metastable phase peakto the stable phase peak), the ionic conductivity is increased.

Meanwhile, the glass as referred to herein means a substance for whichpeaks ascribable to crystals are not observed as a result of an X-raydiffraction measurement, or if peaks ascribable to crystals areobserved, the peak intensity thereof is low (the object is composedmainly of an amorphous substance). On the other hand, the glass ceramicas referred to herein means a substance for which peaks ascribable tocrystals are observed as a result of an X-ray diffraction measurement.The glass ceramic may contain an amorphous part. That is, the glassceramic includes a mixture of glass and glass ceramic.

In the invention, the solid electrolyte before a heat treatment isexpressed as a solid electrolyte glass and the solid electrolyte after aheat treatment is expressed as a solid electrolyte glass ceramic.

In the first solid electrolyte glass of the invention, it is preferredthat the elements excluding oxygen have a composition represented by thefollowing formula (1). It is further preferred that all of the elementscontained in the solid electrolyte glass have a composition representedby the following formula (1):

L_(a)M_(b)P_(c)S_(d)X_(e)  (1)

wherein in the formula, L is an alkali metal; M is one or more elementsselected from B, Al, Si, Ge, As, Se, Sn, Sb, Te, Pb and Bi; and X is oneor more halogen elements selected from I, Cl, Br and F; and

a to e independently satisfy the following formulas:

0<a≦12, 0≦b≦0.2, c=1, 0<d≦9 and 0<e≦9.

The first solid electrolyte of the invention can be synthesized by usingthe following raw materials (1-A), (1-B) and (1-C), for example.

(1-A) alkali metal sulfide

(1-B) compound represented by M′_(m)S_(n)

(1-C) compound represented by M″_(w)X_(y)

wherein in the formula, M′ is B, Al, Si, P or Ge; M″ is Li, Na, B, Al,Si, P, S, Ge, As, Se, Sn, Sb, Te, Pb or Bi; and X is F, Cl, Br or I; wis an integer of 1 to 2; and m, n and y are independently an integer of1 to 10.

As the raw material (1-A), Li₂S (lithium sulfide) and Na₂S (sodiumsulfide) can be given. Among these, lithium sulfide is preferable.

Lithium sulfide is not particularly restricted, but one having highpurity is preferable. Lithium sulfide can be produced by a methoddescribed in JP-A-H07-330312, JP-A-H09-283156, JP-A-2010-163356 andJapanese Patent Application No. 2009-238952.

Specifically, lithium hydroxide and hydrogen sulfide are reacted in ahydrocarbon-based organic solvent at 70° C. to 300° C. to form lithiumhydrosulfide. Then, this reaction liquid is dehydrosulfurized, wherebylithium sulfide can be synthesized (JP-A-2010-163356).

Further, lithium hydroxide and hydrogen sulfide are reacted in a watersolvent at 10° C. to 100° C. to form lithium hydroxide, and then, thisreaction liquid is dehydrosulfurized, whereby lithium sulfide can besynthesized (Japanese Patent Application No. 2009-238952).

As for lithium sulfide, the total content of lithium salts in a sulfuroxide is preferably 0.15 mass % or less, more preferably 0.1 mass % orless, and the content of lithium N-methylaminobutyrate is preferably0.15 mass % or less, more preferably 0.1 mass % or less. If the totalcontent of lithium salts in a sulfur oxide is 0.15 mass % or less, asolid electrolyte obtained by melt quenching or mechanical millingbecomes a glassy electrolyte (complete amorphous). On the other hand, ifthe total content of lithium salts of a sulfur oxide exceeds 0.15 mass%, the resulting electrolyte may be crystalline from the beginning.

If the content of lithium N-methylaminobutyrate is 0.15 mass % or less,a deteriorated product of lithium N-methylaminobutyrate does not lowerthe cycle performance of a lithium ion battery. By using lithium sulfideof which the amount of impurities is decreased, a highly ionicconductive electrolyte can be obtained.

When lithium sulfide is produced by the method described inJP-A-H07-330312 and JP-A-H09-283156, since lithium sulfide containslithium salts or the like of a sulfur oxide, it is preferable to conductpurification.

On the other hand, lithium sulfide produced by the method for producinglithium sulfide disclosed in JP-A-2010-163356 has a significantly smallamount of lithium salts or the like of a sulfur oxide, and hence may beused without purification.

As for preferable purification methods, a purification method describedin WO2005/40039 can be given, for example. Specifically, lithium sulfideobtained as above is washed at a temperature of 100° C. or higher byusing an organic solvent.

As the raw material (1-B), P₂S₃ (phosphorus trisulfide), P₂S₅(phosphorus pentasulfide), SiS₂ (silicon sulfide), Al₂S₃ (aluminumsulfide), GeS₂ (germanium sulfide), B₂S₃ (arsenic trisulfide) or thelike can be used. P₂S₅ is preferable. The raw material (1-B) can be usedin a mixture of two or more.

Industrially producible and commercially available P₂S₅ can be used withno particular restrictions.

As the compound (1-C) that contains a halogen, LiF, LiCl, LiBr, LiI,BCl₃, BBr₃, BI₃, AlF₃, AlBr₃, AlI₃, AlCl₃, SiF₄, SiCl₄, SiCl₃, Si₂Cl₆,SiBr₄, SiBrCl₃, SiBr₂Cl₂, SiI₄, PF₃, PF₅, PCl₃, PCl₅, PBr₃, PI₃, P₂Cl₄,P₂I₄, SF₂, SF₄, SF₆, S₂F₁₀, SCl₂, S₂Cl₂, S₂Br₂, GeF₄, GeCl₄, GeBr₄,GeI₄, GeF₂, GeCl₂, GeBr₂, GeI₂, AsF₃, AsCl₃, AsBr₃, AsI₃, AsF₅, SeF₄,SeF₆, SeCl₂, SeCl₄, Se₂Br₂, SeBr₄, SnF₄, SnCl₄, SnBr₄, SnI₄, SnF₂,SnCl₂, SnBr₂, SnI₂, SbF₃, SbCl₃, SbBr₃, SbI₃, SbF₅, SbCl₅, PbF₄, PbCl₄,PbF₂, PbCl₂, PbBr₂, PbI₂, BiF₃, BiCl₃, BiBr₃, BiI₃, TeF₄, Te₂F₁₀, TeF₆,TeCl₂, TeCl₄, TeBr₂, TeBr₄, TeI₄, NaI, NaF, NaCl, NaBr or the like canbe given. A compound in which M″ is lithium or phosphorus is preferable.Specifically, LiCl, LiBr, LiI, PCl₅, PCl₃, PBr₅ and PBr₃ are preferable,with LiCl, LiBr, LiI and PBr₃ being more preferable.

In addition to the above-mentioned raw materials (1-A) to (1-C), as araw material (1-D), a compound that lowers the glass transitiontemperature (vitrification accelerating agent) may be added. As examplesof the vitrification accelerating agent, inorganic compounds such asLi₃PO₄, Li₄SiO₄, Li₄GeO₄, Li₃BO₃, Li₃AlO₃, Li₃CaO₃, Li₃InO₃, Na₃PO₄,Na₄SiO₄, Na₄GeO₄, Na₃BO₃, Na₃AlO₃, Na₃CaO₃ and Na₃InO₃ can be given.

Other than the above-mentioned raw materials (1-A) to (1-D), a singlesubstance of phosphorus (P), a single substance of sulfur (S), silicon(Si), LiBO₂ (lithium metaborate), LiAlO₃ (lithium aluminate), Na₂S(sodium sulfide), NaBO₂ (sodium metaborate), NaAlO₃ (sodium aluminate),POCl₃, POBr₃ or the like can be used.

Regarding the first solid electrolyte glass of the invention, whenoxygen is contained due to the addition of a vitrification accelerator,a halogen compound that contains oxygen, lithium sulfite in theExamples, or the like, it has a composition represented by the followingformula (1′) of each element including oxygen, for example.

L_(a)M_(b)P_(c)S_(d)X_(e)O_(f)  (1′)

wherein in the formula L is an alkali metal; M is one or more elementsselected from B, Al, Si, Ge, As, Se, Sn, Sb, Te, Pb and Bi; and X is oneor more halogen elements selected from I, Cl, Br and F; and

a to e independently satisfy the following formulas:

0<a≦12, 0≦b≦0.2, c=1, 0<d≦9 and 0<e≦9 and 0<f≦9.

The first solid electrolyte glass of the invention is sulfide-basedglass having a composition shown in the above-mentioned formula (1). Thecomposition is controlled by the mixing ratio of the above-mentioned rawmaterials (1-A) to (1-D).

The mixing ratio of the components (1-A), (1-B) and (1-C) variesdepending on M″ in the component (1-C); i.e. whether M″ is phosphorus orother elements than phosphorus.

When M″ in the component (1-C) is an element other than phosphorus, forexample, the molar ratio of component (1-A):component (1-B) is 65:35 to85:15, preferably (1-A):(1-B)=67:33 to 83:17 (molar ratio), furtherpreferably (1-A):(1-B)=68:32 to 80:20 (molar ratio), and most preferably(1-A):(1-B)=75:25 to 79:21 (molar ratio).

At this time, the ratio of the molar amount of (1-C) relative to thetotal of the molar amounts of the components (1-A) and (1-B) ispreferably 50:50 to 99:1, more preferably [(1-A)+(1-B)]:(1-C)=55:45 to97:3 (molar ratio), further preferably [(1-A)+(1-B)]:(1-C)=60:40 to 96:4(molar ratio) and particularly preferably [(1-A)+(1-B)]:(1-C)=70:30 to96:4 (molar ratio).

When M″ in the component (1-C) is phosphorus, for example, the molarratio of component (1-A):component (1-B) is 60:40 to 90:10, preferably,(1-A):(1-B)=70:30 to 90:10 (molar ratio), more preferably(1-A):(1-B)=72:28 to 88:12 (molar ratio), further preferably(1-A):(1-B)=74:26 to 86:14 (molar ratio), particularly preferably(1-A):(1-B)=75:25 to 85:15 (molar ratio) and most preferably, component(1-A) is lithium sulfide, component (1-B) is phosphorus pentasulfide and(1-A):(1-B)=77:23 to 83:17 (molar ratio).

At this time, the ratio of the molar amount of (1-C) relative to thetotal of the molar amounts of components (1-A) and (1-B) is 50:50 to99:1, more preferably [(1-A)+(1-B)]:(1-C)=80:20 to 98:2 (molar ratio),further preferably [(1-A)+(1-B)]:(1-C)=85:15 to 98:2 (molar ratio) andparticularly preferably [(1-A)+(1-B)]:(1-C)=90:10 to 98:2.

The mixing amount of the raw material (1-D) (vitrification acceleratingagent) is preferably 1 to 10 mol % relative to the total of the rawmaterials (1-A), (1-B) and (1-C), with 1 to 5 mol % being particularlypreferable.

The first solid electrolyte glass of the invention may consistessentially of the above-mentioned raw materials (1-A) to (1-C), andoptionally, the raw material (1-D), or may consist of these components.The “consist essentially of” means that the above-mentioned compositioncomprises mainly the above-mentioned raw materials (1-A) to (1-C), andoptionally, the raw material (1-D); that is, for example, means that theamount ratio of the raw materials (1-A) to (1-D) is 95 wt % or more or98 wt % or more of the total amount of the raw materials.

The first solid electrolyte glass of the invention can be synthesized bymixing the above-mentioned raw materials (1-A) to (1-C) and, optionally,the raw material (1-D), and vitrifying the mixture by a method such as amelt quenching method, mechanical milling method (MM method), a slurrymethod and a solid phase method. Hereinbelow, for each method, anexplanation will be given taking as an example a case where Li₂S is usedas the raw material (1-A) and P₂S₅ is used as the raw material (1-B).

(i) Melt Quenching Method

The melt quenching method is described in JP-A-H06-279049 andWO2005/119706, for example. Specifically, a prescribed amount of P₂S₅,Li₂S and a compound that contains a halogen (raw material (1-C)) aremixed in a mortar to allow them to be in the form of a pellet. Theresulting pellet is put in a quarts tube coated with carbon and vacuumsealed. After allowing them to react at a prescribed reactiontemperature, the reaction product is put in ice for quenching, whereby aglass solid electrolyte is obtained.

The reaction temperature is preferably 400° C. to 1000° C., morepreferably 800° C. to 900° C.

The reaction time is preferably 0.1 hour to 12 hours, more preferably 1to 12 hours.

The quenching temperature of the above-mentioned reaction product isnormally 10° C. or less, preferably 0° C. or less. The cooling rate isnormally about 1 to 10000K/sec, preferably 10 to 10000K/sec.

(ii) Mechanical Milling Method (MM Method)

The MM method is described in JP-A-H11-134937, JP-A-2004-348972 andJP-A-2004-348973, for example.

Specifically, prescribed amounts of P₂S₅, Li₂S and the raw material(1-C) are mixed in a mortar, and the mixture is allowed to react for aprescribed period of time by using various ball mills, for example,whereby a solid electrolyte glass is obtained.

In the MM method using the above-mentioned raw materials, a reaction canbe conducted at room temperature. According to the MM method, there isan advantage that, since a reaction can be conducted at roomtemperature, thermal decomposition of the raw materials does not occur,whereby a solid electrolyte glass having a composition same as that ofcharging can be obtained.

Further, in the MM method, there is also an advantage that,simultaneously with the production of a solid electrolyte glass, a glasssolid electrolyte can be finely pulverized.

The MM method can be conducted by various mills such as a rotary ballmill, a tumbling ball mill, a vibration ball mill, a planetary ball millor the like.

As for the conditions for the MM method, if a planetary ball mill isused, for example, the milling may be conducted for 0.5 hour to 100hours with a rotation speed of several tens to several hundreds rotationper minute.

Further, as described in JP-A-2010-90003, balls differing in diametermay be used in a mixture as balls of a ball mill.

In addition, as described in JP-A-2009-110920 or JP-A-2009-211950, anorganic solvent may be added to the raw material to allow it be in theform of a slurry, and the slurry may be subjected to a MM treatment.

Further, as described in JP-A-2010-30889, the temperature inside themill at the time of a MM treatment may be adjusted.

It is preferred that the temperature of the raw materials at the time ofa MM treatment be 60° C. or higher and 160° C. or lower.

(iii) Slurry Method

The slurry method is described in WO2004/093099 and WO2009/047977.

Specifically, by allowing prescribed amounts of P₂S₅ particles, Li₂Sparticles and the raw material (1-C) to react in an organic solvent fora predetermined period of time, a solid electrolyte can be obtained.

It is preferred that the raw material (1-C) be dissolved in an organicsolvent or be particles.

Here, as described in JP-A-2010-140893, in order to proceed thereaction, a reaction may be conducted while circulating a slurrycontaining raw materials between the beads mill and the reactionapparatus.

Further, as described in WO2009/047977, by pulverizing lithium sulfideas the raw material in advance, a reaction can be proceeded efficiently.

In addition, as described in Japanese Patent Application No.2010-270191, in order to increase the specific surface area of lithiumsulfide as the raw material, it may be immersed in a polar solvent (forexample, methanol, diethyl carbonate, acetonitrile) having a dissolutionparameter of 9.0 or more for a prescribed period of time.

The reaction temperature is preferably 20° C. or higher and 80° C. orlower, more preferably 20° C. or higher and 60° C. or lower.

The reaction time is preferably 1 hour or longer and 16 hours orshorter, and more preferably 2 hours or longer and 14 hours or shorter.

It is preferred that the amount of an organic solvent be such that P₂S₅,Li₂S and the raw material (1-C) as raw materials become in the form of asolution or a slurry by addition of the organic solvent. Normally, theamount of the raw materials (total amount) relative to 1 liter of theorganic solvent is about 0.001 kg or more and 1 kg or less. The amountis preferably 0.005 kg or more and 0.5 kg or less, with 0.01 kg or moreand 0.3 kg or less being particularly preferable.

No particular restrictions are imposed on the type of the organicsolvent. An aprotic organic solvent is particularly preferable.

As for the aprotic organic solvent, an aprotic non-polar organic solvent(for example, a hydrocarbon-based organic solvent), an aprotic polarorganic compound (for example, an amide compound, a lactam compound, aurea compound, an organic sulfur compound, a cyclic organic phosphoruscompound or the like) may preferably be used as a single solvent or amixed solvent.

As the hydrocarbon-based organic solvent, saturated hydrocarbon,unsaturated hydrocarbon or aromatic hydrocarbon can be used.

As the saturated hydrocarbon, hexane, pentane, 2-ethylhexane, heptane,decane, cyclohexane or the like can be given.

As the unsaturated hydrocarbon, hexene, heptene, cyclohexene or the likecan be given.

As the aromatic hydrocarbon, toluene, xylene, decalin,1,2,3,4-tetrahydronaphthalene or the like can be given.

Among them, toluene and xylene are particularly preferable.

It is preferred that the hydrocarbon-based solvent be dehydrated inadvance. Specifically, the water content is preferably 100 wt ppm orless, with 30 wt ppm or less being particularly preferable.

According to need, other solvents may be added to the hydrocarbon-basedsolvent. Specific examples include ketones such as acetone and methylethyl ketone; ethers such as tetrahydrofuran; alcohols such as ethanoland butanol; esters such as ethyl acetate; and halogenated hydrocarbonssuch as dichloromethane and chlorobenzene.

(iv) Solid Phase Method

The solid phase method is stated in “H-J, Deiseroth, et. al., Angew.Chem. Int. Ed. 2008, 47, 755-758”, for example. Specifically, specificamounts of P₂S₅, Li₂S and the raw material (1-C) are mixed in a mortar,followed by heating at 100 to 900° C., whereby a solid electrolyte isobtained.

The production conditions such as the temperature conditions, thetreatment time, and the charged amount or the like of the melt quenchingmethod, the MM method, the slurry method and the solid phase method canbe appropriately adjusted according to equipment used or the like.

As the method for producing a solid electrolyte glass, the MM method,the slurry method or the solid phase method is preferable. Due tocapability of production at a low cost, the MM method and the slurrymethod are more preferable, with the slurry method being particularlypreferable.

In any of the melt quenching method, the MM method, the slurry methodand the solid phase method, the order of mixing is not restricted aslong as the composition of the final solid electrolyte glass is in theabove-mentioned range. For example, in the case of the MM method, aftermixing all of the raw material (1-A), the raw material (1-B) and the rawmaterial (1-C), milling may be conducted; after milling the raw material(1-A) and the raw material (1-B) and then adding the raw material (1-C),further milling may be conducted; after mixing LiBr and P₂S₅, and thenadding Li₂S, further milling may be conducted; or after milling the rawmaterial (1-A) and the raw material (1-C) and then adding the rawmaterial (1-B), further milling may be conducted. Alternatively, after amixture obtained by mixing and milling the raw material (1-A) and theraw material (1-C) and a mixture obtained by mixing and milling the rawmaterial (1-C) and the raw material (1-B) may be mixed, followed byfurther milling.

When mixing is conducted twice or more, two or more different methodsmay be used in combination. For example, after subjecting the rawmaterial (1-A) and the raw material (1-B) to mechanical milling, the rawmaterial (1-C) is mixed, and, the treatment is conducted by the solidphase method. Alternatively, a solid electrolyte glass may be producedin such a manner that a product obtained by treating the raw material(1-A) and the raw material (1-C) by the solid phase method and a productobtained by treating the raw material (1-B) and the raw material (1-C)by the melt quenching method are mixed, and the resulting mixture istreated by the slurry method.

In the first aspect of the invention, it is preferred that the rawmaterial (1-A) and the raw material (1-B) be reacted at first, and thenthe raw material (1-C) is added to allow it to react with a reactionproduct of the raw material (1-A) and the raw material (1-B). As aresult, the distance between the two exothermic peaks can be morewidened.

Further, it is preferred that a step in which a reaction is conducted inan atmosphere with an oxygen concentration of 19 to 21% be included. Forexample, sealing of dry air in a ball mill can be mentioned. As aresult, the distance between the two exothermic peaks can be morewidened.

In the first solid electrolyte glass of the invention, as mentionedabove, two exothermic peaks (crystallization peaks) are observed in adifferential scanning calorimetric measurement in the range of 150° C.or higher and 350° C. or lower. The difference in temperature betweenthe peak top positions of the two exothermic peaks is preferably 20° C.or higher and 150° C. or lower, further preferably 30° C. or higher and130° C. or lower, further preferably 35° C. or higher and 130° C. orlower, and particularly preferably 40° C. or higher and 120° C. orlower. As a result, heat treatment conditions that form only ametastable phase can be milder.

The peak top positions of the two exothermic peaks can be adjusted bythe kind of the raw material, the mixing ratio of each raw material andthe type of production method. Taking a single instance, an electrolyteprecursor is synthesized in advance by using the raw material (1-A) andthe raw material (1-B), and the raw material (1-C) is added to conduct afurther synthesis treatment, and as a result, a distance between eachpeak top position is widened. Further, by conducting each step in thepresence of oxygen, a distance between the peak top positions iswidened.

It is preferred that the two crystallization peaks be present in a rangeof 170° C. or higher and 330° C. or lower, further preferably 175° C. orhigher and 320° C. or lower, and particularly preferably 180° C. orhigher and 310° C. or lower.

B. Solid Electrolyte Glass Ceramic

The solid electrolyte glass ceramic according to the first aspect of theinvention (hereinafter often referred to as the “first solid electrolyteglass ceramic”) is obtained by subjecting the above-mentioned firstsolid electrolyte glass of the invention to a heat treatment at atemperature between the above-mentioned two exothermic peaks.

Within a range that does not exceed the exothermic peak (Tc2) on thehigh-temperature side, the heat treatment temperature is preferably atemperature that is the peak temperature (Tc1) of the exothermic peak onthe low-temperature side or higher and (Tc1+30°) C. or lower,particularly preferably equal to or higher than (Tc1+5°) C. and equal toor lower than (Tc1+25°) C.

Regarding the intensity of each peak before and after the heattreatment, it is desired that, as for the exothermic peak on thelow-temperature side, the intensity after the heat treatment be almostzero relative to the peak intensity before the heat treatment, and thatthe exothermic peak on the high-temperature side have 70% or more of theintensity as compared with that before the heat treatment. As a result,a sufficient amount of a metastable phase can be formed.

The heating time is preferably 0.005 minutes or longer and 10 hours orshorter. Further preferably, the heating time is 0.005 minutes or longerand 5 hours or shorter, with 0.01 minute or longer and 3 hours orshorter being particularly preferable.

The heating method is not particularly restricted. Heating may beconducted slowly or rapidly to a prescribed temperature.

It is preferred that the heating be conducted at a temperature equal toor lower than a dew point −40° C., more preferably at a temperatureequal to or lower than a dew point −60° C. The atmosphere at the time ofheating may be normal pressure or may be reduced pressure. Theatmosphere may be air or an inert gas.

The first solid electrolyte glass ceramic of the invention has a highionic conductivity. For example, the ionic conductivity may be 1×10⁻³S/cm or more, more preferably 1.5×10⁻³ S/cm or more. Due to such anionic conductivity, an all-solid battery using the first solidelectrolyte glass ceramic of the invention can realize a high output.

The first solid electrolyte glass ceramic of the invention is hardlyhydrolyzed and has a high ionic conductivity, and hence, is preferableas a constituting material for an all-solid battery such as a solidelectrolyte layer.

Hereinbelow, an explanation will be made on the second aspect of theinvention.

The solid electrolyte according to the second aspect of the invention(hereinafter often referred to as the second solid electrolyte)comprises a lithium (Li) element, a phosphorus (P) element, a sulfur (S)element and a halogen element, and satisfies the following conditions(1) and (2).

(1) Having a peak ascribable to crystals at 76.9±0.5 ppm, 87.4±0.6 ppmand 92.5±0.6 ppm of the solid ³¹PNMR spectrum.(2) Ratio (x_(c)) of crystals that generate the peak (1) relative to theentire solid electrolyte is 60 mol % to 100 mol %.

The second solid electrolyte has low reactivity and has high lithium ionconductivity.

The two peaks in the condition (1) are observed when highly ionicconductive crystal components are present in the solid electrolyte.

The condition (2) specifies the ratio x_(c) of the above-mentionedcrystals in the solid electrolyte.

The measurement method and the measurement conditions of the solid³¹PNMR spectrum and x_(c) will be explained in detail in the Examples.

If the highly ionic conductive crystal components are present in aprescribed amount or larger (specifically, 60 mol % or more) in a solidelectrolyte, lithium ions mainly move in highly ionic conductivecrystals.

Therefore, as compared with a case where lithium ions move in anon-crystalline part (glass part) or crystal lattices that do notexhibit high ionic conductivity (for example, P₂S₆ ⁴⁻) of a solidelectrolyte, lithium ion conductivity is improved.

x_(c) is preferably 65 mol % to 100 mol %, more preferably 80 mol % to100 mol %, further preferably 90 mol % to 100 mol %, and most preferably93 mol % to 100 mol %.

x_(c) can be controlled by adjusting the heat-treatment time and theheat-treatment temperature of the sulfide glass as the raw material.

The halogen contained in the second solid electrolyte of the inventionis preferably one halogen atom selected from F, Cl, Br and I, and Cl, Bror I is more preferable, with Br or I being particularly preferable.

It is preferred that the second solid electrolyte of the invention havethe composition represented by the following formula (1):

Li_(a)M_(b)P_(c)S_(d)X_(e)  (1)

wherein in the formula M is B, Al, Si, Ge, As, Se, Sn, Sb, Te, Pb or Bi,or a combination thereof; X is I, CI, Br or F, or a combination thereof;and a to e satisfy 0<a≦12, 0≦b≦0.2, c=1, 0<d≦9 and 0<e≦9.

In the formula (1), M is an element represented by the following formula(2).

B_(f)Al_(g)Si_(h)Ge_(i)As_(j)Se_(k)Sn_(l)Sb_(m)Te_(n)Pb_(o)Bi_(p)  (2)

In the formula (2), f to p are independently a composition ratio of eachelement. f, g, h, i, j, k, I, m, o and p are independently 0 or more and1 or less, and f+g+h+i+j+k+l+m+n+o+p=1. The formula (2) shows oneelement or a combination of two or more elements selected from B, Al,Si, P, S, Ge, As, Se, Sn, Sb, Te, Pb and Bi.

In the formula (2), a case where i, j, k, I, m, n, o and p are 0, thatis B_(f)Al_(g)Si_(h) (f, g and h are 0 or more and 1 or less andf+g+h=1) is preferable.

In the formula (1), X is represented by the following formula (3).

F_(s)I_(t)Cl_(u)Br_(v)  (3)

In the formula (3), s, t, u and v are independently a composition ratioof each element s, t, u and v are independently 0 or more and 1 or less,and s+t+u+v=1. The formula (3) shows one halogen element or acombination of two or more halogen elements selected from F, Cl, Br andI.

It is preferred that s and t be 0, that is, Cl_(u)Br_(v) (u and v areindependently 0 or more and 1 or less, and u+v=1). It is more preferredthat s, t and u be 0, that is, Br.

X is preferably one halogen atom selected from F, Cl, Br and I,particularly preferably I, Br or Cl, with Br being more preferable.

In the formula (1), a to e are independently a composition ratio of eachelement and satisfy 0<a≦12, 0≦b≦0.2, c=1, 0<d≦9 and 0<e≦9.

b is preferably 0, and the ratio of a, c, d and e (a:c:d:e) ispreferably a:c:d:e=1 to 9:1:3 to 7:0.05 to 3, further preferablya:c:d:e=2 to 6.5:1:3.5 to 5:0.1 to 1.5. Most preferably, a:c:d:e=2 to6.5:1:3.5 to 4.95:0.1 to 1.5.

d is preferably 4.

The composition ratio of each element can be controlled by adjusting theamount of the raw material compounds when producing the second solidelectrolyte of the invention or the electrolyte precursor.

In the second aspect, the “solid electrolyte” corresponds to the solidelectrolyte glass of the first aspect and the “electrolyte precursor”corresponds to the solid electrolyte glass of the first aspect.

The second solid electrolyte of the invention comprises a Li element, aP element, a S element and a halogen element. The second solidelectrolyte of the invention may comprise a Li element, a P element, a Selement and a halogen element as main components, and may contain otherelements such as an oxygen element.

Specifically, 98 at % or more, 99 at % or more or 100 at % (excludingimpurities inevitably mixed in) of the elements constituting the secondsolid electrolyte of the invention may be Li, P, S and a halogen.

The second solid electrolyte of the invention can be produced bysubjecting sulfide glass that contains lithium (Li), phosphorus (P),sulfur (S) and halogen elements (F, Cl, Br and I) to a heat treatmentmentioned later.

The solid electrolyte can be produced by reacting the raw materials(2-A) to (2-C) and the raw material (2-D) (a compound that contains ahalogen element) by prescribed methods.

Hereinbelow, an explanation will be made of each raw material.

Raw Material (2-A): Lithium Compound

As the lithium compound, Li₂S (lithium sulfide), Li₄SiO₄ (lithiumorthosilicate), Li₃PO₄ (lithium phosphate), Li₄GeO₄ (lithium germanate),LiBO₂ (lithium metaborate), LiAlO₃ (lithium aluminate) or the like canbe used. These can be used in a mixture of two or more.

As the preferable raw material, Li₂S (lithium sulfide) can be given.

No specific restrictions are imposed on lithium sulfide, but one havinga high purity is preferable. Lithium sulfide can be produced by a methoddescribed in JP-A-07-330312, JP-A-H09-283156, JP-A-2010-163356 andJP-A-2011-084438, for example.

Specifically, lithium hydroxide and hydrogen sulfide are reacted at 70°C. to 300° C. in a hydrocarbon-based organic solvent to produce lithiumhydrosulfide. Then, this reaction liquid is dehydrosulfurized, wherebylithium sulfide can be synthesized (JP-A-2010-163356).

Alternatively, lithium hydroxide and hydrogen sulfide are reacted at 10°C. to 100° C. in a water solvent to produce lithium hydrosulfide. Then,this reaction liquid is dehydrosulfurized, whereby lithium sulfide canbe synthesized (JP-A-2011-084438).

As for lithium sulfide, the total content of lithium salts in a sulfuroxide is preferably 0.15 mass % or less, more preferably 0.1 mass % orless. The content of lithium N-methylaminobutyrate is 0.15 mass % orless, more preferably 0.1 mass % or less. If the total content oflithium salts in a sulfur oxide is preferably 0.15 mass % or less, asolid electrolyte obtained by the melt quenching method or themechanical milling method becomes glassy electrolyte (completeamorphous). On the other hand, if the total content of lithium salts ina sulfur oxide exceeds 0.15 mass %, the resulting electrolyte may becomecrystalline from the beginning.

If the content of lithium N-methylaminobutyrate is 0.15 mass % or less,a deteriorated product of lithium N-methylaminobutyrate does not lowerthe cycle performance of a lithium ion battery. By using lithium sulfideof which the amount of impurities is decreased, a highly ionicconductive electrolyte can be obtained.

If lithium sulfide is produced by a method described in JP-A-H07-330312and JP-A-H09-283156, since lithium sulfide contains lithium salts or thelike of a sulfur oxide, it is preferable to conduct purification.

On the other hand, lithium sulfide produced by a method for producinglithium sulfide described in JP-A-2010-163356 has a significantly smallamount of lithium salts or the like of a sulfur oxide, and hence, can beused without purification.

As the preferable purification method, a purification method describedin WO2005/40039, or the like, can be given, for example. Specifically,lithium sulfide obtained as above is washed at a temperature of 100° C.or higher by using an organic solvent.

Raw Material (2-B): Phosphorus Compound

As the phosphorus compound, phosphorus sulfide such as P₂S₃ (phosphorustrisulfide) and P₂S₅ (phosphorus pentasulfide), a single substance ofphosphorus (P), Na₃PO₄ (sodium phosphate) or the like can be mentioned.

P₂S₅ is preferable. P₂S₅ can be used without particular restrictions aslong as it is produced and sold on an industrial basis.

Raw Material (2-C): Other Compounds

In addition to the above-mentioned raw materials (2-A) and (2-B), asingle substance of sulfur (S), silicon (Si), Na₂S (sodium sulfide),SiS₂ (silicon sulfide), Al₂S₃ (aluminum sulfide), GeS₂ (germaniumsulfide), B₂S₃ (arsenic trisulfide), Na₄SiO₄ (sodium orthosilicate),NaAlO₃ (sodium aluminate), Na₄GeO₄ (sodium germanate), NaBO₂ (sodiummetaborate) or the like can be used. They can be used in a mixture oftwo or more.

Raw Material (2-D): Halogen Compound

As the compound that comprises a halogen element, a compound representedby the following formula (4) can be used. One compound may be used or aplurality of compounds may be used.

M_(w)-X_(x)  (4)

In the formula (4), M is Li, B, Al, Si, P, S, Ge, As, Se, Sn, Sb, Te, Pbor Bi. P or Li is particularly preferable. w is an arbitrary integer of1 to 2, and x is an arbitrary integer of 1 to 10.

It is preferred that X be one halogen atom selected from F, Cl, Br andI. X is particularly preferably I, Br or Cl, with Br being morepreferable.

As the raw material (2-D), specific examples thereof include LiF, LiCl,LiBr, LiI, BCl₃, BBr₃, BI₃, AlF₃, AlBr₃, AlI₃, AlCl₃, SiF₄, SiCl₄,SiCl₃, Si₂Cl₆, SiBr₄, SiBrCl₃, SiBr₂Cl₂, SiI₄, PF₃, PF₅, PCl₃, PCl₅,POCl₃, PBr₃, POBr₃, PI₃, P₂Cl₄, P₂I₄, SF₂, SF₄, SF₆, S₂F₁₀, SCl₂, S₂Cl₂,S₂Br₂, GeF₄, GeCl₄, GeBr₄, GeI₄, GeF₂, GeCl₂, GeBr₂, GeI₂, AsF₃, AsCl₃,AsBr₃, AsI₃, AsF₅, SeF₄, SeF₆, SeCl₂, SeCl₄, Se₂Br₂, SeBr₄, SnF₄, SnCl₄,SnBr₄, SnI₄, SnF₂, SnCl₂, SnBr₂, SnI₂, SbF₃, SbCl₃, SbBr₃, SbI₃, SbF₅,SbCl₅, PbF₄, PbCl₄, PbF₂, PbCl₂, PbBr₂, PbI₂, BiF₃, BiCl₃, BiBr₃, BiI₃,TeF₄, Te₂F₁₀, TeF₆, TeCl₂, TeCl₄, TeBr₂, TeBr₄, TeI₄, NaI, NaF, NaCl andNaBr. LiCl, LiBr, LiI, PCl₅, PCl₃, PBr₅ and PBr₃ are preferable, withLiCl, LiBr, LiI and PBr₃ being more preferable.

In addition to the above-mentioned raw materials (2-A) to (2-D), acompound that lowers the glass transition temperature (vitrificationaccelerator) may be added. As examples of the vitrification accelerator,inorganic compounds such as Li₃PO₄, Li₄SiO₄, Li₄GeO₄, Li₃BO₃, Li₃AlO₃,Li₃CaO₃, Li₃InO₃, Na₃PO₄, Na₄SiO₄, Na₄GeO₄, Na₃BO₃, Na₃AlO₃, Na₃CaO₃,Na₃InO₃ or the like can be mentioned.

Hereinbelow, an explanation will be made on the method for producing asolid electrolyte (glass) using lithium sulfide, phosphorus pentasulfideand a halogen compound as the raw materials.

When a halogen compound is lithium halide, the ratio (molar ratio) oflithium sulfide:phosphorus pentasulfide is 65:35 to 85:15, for example,preferably 67:33 to 83:17, more preferably 67:33 to 80:20, with 72:28 to78:22 being most preferable.

In this case, the molar ratio of lithium halide relative to the total ofthe molar amounts of lithium sulfide and phosphorus pentasulfide ispreferably 50:50 to 99:1, more preferably 55:45 to 97:3, furtherpreferably 60:40 to 96:4, and particularly preferably 70:30 to 96:4.

If the halogen compound is other than lithium halide, the mixing ratio(molar ratio) of lithium sulfide and phosphorus pentasulfide is 60:40 to90:10, for example, preferably 70:30 to 90:10, more preferably 72:28 to88:12, further preferably 74:26 to 86:14, particularly preferably 75:25to 85:15, with 77:23 to 83:17 being most preferable.

At this time, the molar ratio of a halogen compound relative to thetotal of the molar amounts of lithium sulfide and phosphoruspentasulfide is 50:50 to 99:1, more preferably 80:20 to 98:2, furtherpreferably 85:15 to 98:2, with 90:10 to 98:2 being particularlypreferable.

By subjecting a material obtained by mixing lithium sulfide, phosphoruspentasulfide and a halogen compound in the above-mentioned mixing ratioto a treatment by the melt quenching method, the mechanical millingmethod (hereinafter “mechanical milling” is appropriately referred to asthe “MM”), a slurry method in which raw materials are reacted in anorganic solvent, a solid phase method or the like, a solid electrolyte(glass) is produced.

The melt quenching method, the mechanical milling method, the slurrymethod and the solid phase method as mentioned above are the same as themelt quenching method, the mechanical milling method, the slurry methodand the solid phase method mentioned in the first aspect of theinvention.

In any of the melt quenching method, the MM method, the slurry methodand the solid phase method, the order of mixing may be such that thecomposition of the final precursor be in the above-mentioned range. Forexample, if it is the mechanical milling method, milling may beconducted after mixing all of Li₂S, P₂S₅ and the halogen compound;milling may be conducted after milling Li₂S and P₂S₅, followed byfurther milling after addition of the halogen compound; milling may beconducted after milling the halogen compound and P₂S₅, followed byfurther milling after addition of Li₂S; or milling may be conductedafter milling Li₂S and the halogen compound, followed by further millingafter addition of P₂S₅.

Alternatively, milling may be conducted in such a manner that a mixtureobtained by mixing and milling Li₂S and the halogen compound and amixture obtained by mixing and milling the halogen compound and P₂S₅ aremixed, followed by further milling. It is preferred that the Li₂S andP₂S₅ be reacted to obtain a solid electrolyte glass that does notcontain the halogen compound, and the halogen compound is mixed andreacted. By conducting a reaction by this procedure, effects that Tc1(mentioned later) is lowered are exhibited.

In addition to the methods mentioned above, when mixing is conductedtwice or more, two or more different methods may be used in combination.For example, a solid electrolyte (glass) is produced by after subjectingLi₂S and P₂S₅ to a mechanical milling, mixing LiBr, and treating by thesolid phase method. Alternatively, a product obtained by treating Li₂Sand LiBr by the solid phase method and a product obtained by treatingP₂S₅ and LiBr by the melt quenching method are mixed, and the resultingmixture is treated by the slurry method, whereby a solid electrolyte(glass) is produced.

By subjecting the obtained solid electrolyte (glass) to a heattreatment, the second solid electrolyte of the invention is obtained.

Specifically, when two crystallization temperatures (peaks) are observedby thermo-physical property measurement, a heat treatment is conductedbetween a first crystallization peak temperature (Tc1) on thelow-temperature side and a second crystallization peak temperature (Tc2)on the high-temperature side. At this time, the heat-treatmenttemperature is normally 150° C. to 360° C., for example, 160° C. orhigher and 350° C. or lower, 180° C. or higher and 310° C. or lower,180° C. or higher and 290° C. or lower, and 190° C. or higher and 270°C. or lower.

The heating temperature is more preferably Tc1 or higher and Tc2 orlower, and further preferably (Tc1+10° C.) or higher and Tc2 or lower.

The heating temperature is preferably equal to or higher than the glasstransition temperature (Tg) of the solid electrolyte (glass) and isequal to or lower than Tc2. If the heating temperature is lower than theTg of the solid electrolyte (glass), the production time may besignificantly prolonged. On the other hand, if the heating temperatureexceeds Tc2, the resulting solid electrolyte (glass ceramics) maycontain impurities or the like, leading to lowering in ionicconductivity.

The heating temperature is preferably Tc1 or higher and is equal to orlower than an intermediate of Tc1 and Tc2, more preferably Tc1 or higherand is equal to or lower than an intermediate of Tc1 and theabove-mentioned intermediate.

If two crystallization temperatures (peak) are not observed bythermo-physical property measurement, a solid electrolyte that containsa lithium (Li) element, a phosphorus (P) element, a sulfur (S) elementand a halogen element and has a crystallization degree of 60% or morecannot be obtained.

In the second solid electrolyte of the invention, the width of the twoexothermic peaks (crystallization peaks), i.e. the difference betweenTc1 and Tc2, be 20 to 150° C., is preferably 20 to 100° C.

The crystallization temperature (peak) can be specified by means of adifferential thermo-gravimetric apparatus (TGA/DSC1, manufactured byMettler Toledo International Inc.) or by differential scanningcalorimetric apparatus (Diamond DSC manufactured by PerkinElmer Co.,Ltd.) and by using about 20 mg of the solid electrolyte (glass) at arate of 10° C./min.

The crystallization temperature or the like may change according to thetemperature-elevating speed or the like. Therefore, it is required toconduct a heat treatment based on Tc measured at a rate closer to thetemperature-elevating rate for the heat treatment. Accordingly, when atreatment is conducted at a temperature-elevating rate other than thatmentioned in the Examples, although the optimum heat treatmenttemperature varies, it is desired that a heat treatment be conducted atthe above-mentioned conditions based on Tc that is measured at atemperature-elevating rate at which the heat treatment is conducted.

The heating time is preferably 0.005 minutes or longer and 10 hours orshorter, more preferably 0.005 minutes or longer and 5 hours or shorter,with 0.01 minutes or longer and 3 hours or shorter being particularlypreferable.

The temperature-elevating method is not particularly restricted. Heatingmay be conducted slowly or rapidly to a prescribed temperature.

It is preferred that the heating be conducted at a temperature equal toor lower than a dew point −40° C., more preferably at a temperatureequal to or lower than a dew point −60° C. The atmosphere at the time ofheating may be normal pressure or may be reduced pressure. Theatmosphere may be air or an inert gas.

The second solid electrolyte of the invention is hardly hydrolyzed andhas a high ionic conductivity, and hence, is suitable as a constitutingmaterial for a battery such as a solid electrolyte layer.

The first solid electrolyte glass and/or the solid electrolyte glassceramic of the invention, and the second solid electrolyte of theinvention can be a positive electrode mix by mixing with a positiveelectrode active material. Further, by mixing with a negative electrodeactive material, it can be a negative electrode mix.

The first solid electrolyte glass and/or the solid electrolyte glassceramic of the invention, and the second solid electrolyte of theinvention can be used as a material for a solid electrolyte layer of anall-solid battery.

As the positive electrode active material that can be used in thepositive electrode mix of the invention, a material which a lithium ioncan be inserted into or removed therefrom, a material known as thepositive electrode active material in the field of a battery can beused.

For example, oxides such as V₂O₅, LiCoO₂, LiNiO₂, LiMnO₂, LiMn₂O₄,Li(Ni_(a)Co_(b)Mn_(c))O₂ (here, 0<a<1, 0<b<1, 0<c<1, a+b+c=1),LiNi_(1-Y)Co_(Y)O₂, LiCo_(1-Y)Mn_(Y)O₂, LiNi_(1-Y)Mn_(Y)O₂ (here,0≦Y<1), Li(Ni_(a)Co_(b)Mn_(c))O₄ (0<a<2, 0<b<2, 0<c<2, a+b+c=2),LiMn_(2-Z)Ni_(Z)O₄, LiMn_(2-Z)Co_(Z)Co₄ (here, 0<Z<2), LiCoPO₄, LiFePO₄,bismuth oxide (Bi₂O₃), bismuth plumbate (Bi₂Pb₂O₅), copper oxide (CuO),vanadium oxide (V₆O₁₃), Li_(x)CoO₂, Li_(x)NiO₂, Li_(x)Mn₂O₄,Li_(x)FePO₄, Li_(x)CoPO₄, Li_(x)Mn_(1/3)Ni_(1/3)Co_(1/3)O₂ andLi_(x)Mn_(1.5)Ni_(0.5)O₂ can be given. As for other positive electrodeactive materials than those mentioned above, as the sulfide-based activematerial, for example, a single substance of sulfur(S), titanium sulfide(TiS₂), molybdenum sulfide (MoS₂), iron sulfide (FeS, FeS₂), coppersulfide (CuS) and nickel sulfide (Ni₃S₂), lithium sulfide (Li₂S), anorganic disulfide compound, a carbon sulfide compound, sulfur, niobiumselenide (NbSe₃), indium metal or the like can be used. S and Li₂Shaving a high theoretical capacity can be preferably used.

The organic disulfide compound and the carbon sulfide compound areexemplified below.

In the formulas (A) to (C), Xs are independently a substituent, n and mare independently an integer of 1 to 2 and p and q are independently aninteger of 1 to 4.

In the formula (D), Zs are independently —S— or —NH—, and n is aninteger showing a repeating number of 2 to 300.

As the negative electrode active material that can be used in thepositive electrode mix of the invention, a material which a lithium ioncan be inserted into or removed therefrom and a material known as thenegative electrode active material in the field of a battery can beused.

For example, a carbon material; specifically, artificial graphite,graphite carbon fibers, resin baked carbon, thermally decomposedvapor-grown carbon, coke, mesocarbon microbeads (MCMB), furfuryl alcoholresin baked carbon, polyacene, pitch-based carbon fibers, vapor-growncarbon fibers, natural graphite, hardly graphitizable carbon or the likecan be given. A mixture of these may be used. Among them, artificialgraphite is preferable.

In addition, a metal such as lithium, indium, aluminum and silicon or analloy obtained by combining these metals with other elements andcompounds can be used as a negative electrode material. Among them,silicon, tin and lithium having a high theoretical capacity arepreferable.

In the positive electrode mix, the negative electrode mix and the solidelectrolyte layer of the invention, a binder, a conductive aid or thelike may be added, if necessary.

As the binder, a fluorine-containing resin such aspolytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), andfluorine rubber, a thermoplastic resin such as polypropylene andpolyethylene, an ethylene-propylene-diene monomer (EPDM), sulfonatedEPDM, natural butyl rubber (NBR) or the like can be used singly or in amixture of two or more. In addition, a cellulose-based binder as awater-based binder, a water dispersion of styrene-butadiene rubber (SBR)or the like can also be used.

The conductive aid have conductivity. The conductivity of the conductiveaid is preferably 1×10³ S/cm or more, more preferably 1×10⁵ S/cm ormore.

As the conductive aid, a material selected from a carbon material, metalpowder and a metal compound, and a mixture thereof can be given.

As specific examples of the conductive aid, a material that contains atleast one element selected from the group consisting of carbon, nickel,copper, aluminum, indium, silver, cobalt, magnesium, lithium, chromium,gold, ruthenium, platinum, beryllium, iridium, molybdenum, niobium,osmium, rhodium, tungsten, and zinc. The conductive aid is morepreferably a single substance of carbon having a high conductivity, asingle substance, a mixture or a compound of a metal including carbon,nickel, copper, silver, cobalt, magnesium, lithium, ruthenium, gold,platinum, niobium, osmium or rhodium.

Specific examples of the carbon material include carbon black such asKetjen black, acetylene black, denka black, thermal black and channelblack, graphite, carbon fibers, activated carbon or the like. These canbe used singly or in combination of two or more.

Among these, acetylene black, denka black and Ketjen black having a highelectron conductivity are preferable.

The positive electrode mix, the negative electrode mix and the solidelectrolyte layer of the invention may contain other electrolytesaccording to the purpose, in addition to the first solid electrolyteglass or the solid electrolyte glass ceramic or the second solidelectrolyte of the invention.

As the other electrolytes, a polymer-based solid electrolyte, anoxide-based electrolyte and a sulfide-based solid electrolyte can begiven.

No specific restrictions are imposed on the polymer-based solidelectrolyte. For example, as disclosed in JP-A-2010-262860, materialsthat can be used as a polymer electrolyte such as a fluorine resin,polyethylene oxide, polyacrylonitrile, polyacrylate or its derivatives,copolymers or the like can be given.

As the fluorine resin, for example, those comprising vinilidene fluoride(VdF), hexafluoropropylene (HFP), tetrafluoroethylene (TFE) or thederivatives thereof as structural units can be given. Specifically,homopolymers such as vinylidene polyfluoride (PVdF),polyhexafluoropropylene (PHFP), polytetrafluoroethylene (PTFE), binarycopolymers or tertiary copolymers such as copolymer of VdF and HFP(hereinafter, these copolymers may be referred to as “P(VdF-HFP)”) canbe given.

As the oxide-based solid electrolyte, LiN, LISICONs, Thio-LISICONs andcrystals having a Perovskites structure such as La_(0.55)Li_(0.35)TiO₃,LiTi₂P₃O₁₂ having a NASICON structure, and electrolytes obtained bycrystallization of these can be used.

In the all-solid battery of the invention, at least one of the positiveelectrode layer, the electrolyte layer and the negative electrode layercontains the first solid electrolyte glass or the solid electrolyteglass ceramic, or the second solid electrolyte of the invention. Eachlayer can be produced by a known method.

Other constitutions of the all-solid battery of the invention are notparticularly restricted as long as the above-mentioned first solidelectrolyte glass or the solid electrolyte glass ceramic, or the secondsolid electrolyte of the invention is used. For example, an all-solidbattery provided with a positive electrode layer formed of theabove-mentioned positive electrode mix, an all-solid battery providedwith a negative electrode layer formed of the above-mentioned negativeelectrode mix and an all-solid battery provided with the above-mentionedsolid electrolyte can be mentioned.

When the positive electrode layer, the negative electrode layer, and thesolid electrolyte layer are produced by using the above-mentioned firstsolid electrolyte glass, after forming a layer containing the solidelectrode glass, a heat treatment is conducted at a temperature betweenexothermic peak temperatures of the two exothermic peaks that areseparated from each other in a temperature range of 150° C. to 350° C.as determined by a differential scanning calorimetric measurement (in adry nitrogen atmosphere at a temperature-elevating speed of 10° C./minfrom 20 to 600° C.), whereby the all-solid battery of the invention canbe produced.

It is preferred that the positive electrode layer contain a positiveelectrode active material, an electrolyte and a conductive aid. Further,it may contain a binder. In the positive electrode layer, no specificrestrictions are imposed on the amount ratio of the positive electrodeactive material, the electrolyte, the conductive aid or the like, and aknown amount ratio can be used.

It is preferred that the thickness of the positive electrode layer be0.01 mm or more and 10 mm or less.

The positive electrode layer can be produced by a known method. It canbe produced by a coating method and an electrostatic method (anelectrostatic spray method, an electrostatic screen method or the like),for example.

It is preferred that the negative electrode layer contain a negativeelectrode active material, an electrolyte and a conductive aid. Further,it may contain a binder. The method for forming or the thickness of thenegative electrode layer are the same as that in the positive electrodelayer.

It is preferred that the solid electrolyte in the solid electrolytelayer be fused. Here, the “fused” means that part of the solidelectrolyte particles is dissolved and the dissolved part is integratedwith other solid electrolyte particles.

The solid electrolyte layer may be in the form of a plate of the solidelectrolyte. It includes a case where part or all of the solidelectrolyte particles are dissolved to be in the form of a plate.

It is preferred that the thickness of the electrolyte layer be 0.001 mmor more and 1 mm or less.

It is preferred that the all-solid battery of the invention contain acurrent collector in addition to the positive electrode layer, the solidelectrolyte layer and the negative electrode layer. As the currentcollector, a known current collector can be used. For example, a layerobtained by coating an element that reacts with a sulfide-based solidelectrolyte, such as Au, Pt, Al, Ti or Cu, with Au or the like can beused.

The all-solid battery of the invention can be used as a battery thatuses an alkali metal-based electrolyte such as a lithium ion battery anda sodium ion battery, or a battery that uses a divalent cation-basedelectrolyte such as a magnesium ion.

EXAMPLES

The invention will be described in more detail with reference to thefollowing Examples.

Production Example 1 Production of Lithium Sulfide (Li₂S)

Lithium sulfide was produced and purified in accordance with the methoddescribed in the Examples of WO2005/040039A1. Specifically, it wasproduced and purified as follows.

(1) Production of Lithium Sulfide

In a 10 liter-autoclave provided with a stirring blade, 3326.4 g (33.6mol) of N-methyl-2-pyrrolidone (NMP) and 287.4 g (12 mol) of lithiumhydroxide were charged, stirred at a speed of 300 rpm and heated to 130°C. After the heating, hydrogen sulfide was blown to the liquid at asupply speed of 3 liter/min for 2 hours.

Subsequently, the reaction liquid was heated in a nitrogen stream (200cc/min), and part of the reacted hydrogen sulfide was dehydrosulfurized.As the temperature was elevated, water produced as a by-product by thereaction of hydrogen sulfide and lithium hydroxide starts to evaporate.This water was condensed by means of a condenser and withdrawn outsidethe system. With distillation off of the water outside the system, thetemperature of the reaction liquid was increased. When the temperatureof the reaction liquid reached 180° C., the heating was stopped and thetemperature was retained at a certain temperature. After completion ofthe dehydrosulfurization reaction (about 80 minutes), the reaction wascompleted, whereby lithium sulfide was obtained.

(2) Purification of Lithium Sulfide

NMP in 500 mL of the slurry reaction solution obtained in (1) above(NMP-lithium sulfide slurry) was subjected to decantation. 100 mL ofdehydrated NMP was added, and stirred at 105° C. for about 1 hour. Atthat temperature, NMP was subjected to decantation. Further, 100 mL ofNMP was added, and the mixture was stirred at 105° C. for about 1 hour.At that temperature, NMP was subjected to decantation. The similaroperation was repeated 4 times in total. After completion of thedecantation, lithium sulfide was dried for 3 hours at 230° C. (atemperature that is equal to or higher than the boiling temperature ofNMP) under normal pressure and under nitrogen stream. The content ofimpurities in the resulting lithium sulfide was measured.

The content of each of the sulfur oxides of lithium sulfite (Li₂SO₃),lithium sulfate (Li₂SO₄) and lithium thiosulfate (Li₂S₂O₃) and thecontent of lithium N-methylaminobutyrate (LMAB) were quantified by ionchromatography. As a result, the total content of sulfur oxides wasfound to be 0.13 mass % and the content of LMAB was found to be 0.07mass %.

Example 1 Raw Material Ratio:Li₂S/P₂S₅/LiBr=75/25/16.8):MM Method

(1) Synthesis of solid electrolyte glass

0.337 g (0.00717 mol) of lithium sulfide produced in Production Example1, 0.532 g (0.00239 mol) of phosphorus pentasulfide (manufactured bySigma-Aldrich Co.) and 0.140 g (0.00161 mol) of lithium bromide(manufactured by Sigma-Aldrich Co.) were mixed sufficiently in a glovebox in an argon atmosphere. Then, the mixed power and 10 zirconia balls(each having a diameter of 10 mm) were put in an alumina pot of aplanetary ball mill (P-7; manufactured by Fritsch) and completelysealed. The inside of the pot was argon atmosphere.

For initial several minutes, the planetary ball mill was rotated at alow speed (100 rpm) to mix lithium sulfide and phosphorus pentasulfidesufficiently. Thereafter, the rotation speed of the planetary ball millwas raised gradually to 370 rpm. With the rotation speed of theplanetary ball mill being 370 rpm, mechanical milling was conducted for20 hours.

FIGS. 1 and 2 show the results of the analysis by the differentialscanning calorimetric measurement.

When the peak on the low-temperature side was taken as the first peakand the peak on the high-temperature side was taken as the second peak,among the exothermic peaks observed in a range of 150° C. to 350° C.,the position of each peak top (Tc1 and Tc2) and the temperaturedifferences between the peaks (ΔT) are shown in Table 1.

Meanwhile, the differential scanning calorimetric measurement wasconducted in a dry nitrogen atmosphere at a temperature-elevation rateof 10° C./min from 20 to 600° C. A differential thermo-gravimetricmeasurement apparatus (TGA/DSC1 manufactured by Mettler-ToledoInternational Inc.) was used with about 20 mg of the solid electrolyteglass.

(2) Synthesis of Solid Electrolyte Glass Ceramic

The obtained solid electrolyte glass was subjected to a heat treatmentin an argon atmosphere for 2 hours at a temperature (230° C.) betweenthe two exothermic peaks.

The results of the differential thermal analysis after the heattreatment are shown in FIG. 1.

It can be confirmed that, as a result of the heat treatment, the peak onthe low-temperature side disappeared and only the second peak on thehigh-temperature side appeared.

In the differential thermal analysis measurement, when the integratedintensity of the first peak and the integrated intensity of the secondpeak before the heat treatment are taken as Hc1p and Hc2p, respectively,and the integrated intensity of the first peak and the integratedintensity of the second peak after the heat treatment are taken as Hc1and Hc2, respectively, the ratio of the peak intensity before and afterthe heat treatment (Hc1/Hc1p and Hc2/Hc2p) is shown in Table 1.

In the differential thermal analysis results, the peak value wasintegrated by using an analysis software attached to the apparatus.Specifically, the curve of the differential thermal analysis result wasstandardized by the weight, and the integration range was specified andintegration was conducted. As the base line, one obtained byapproximating a range of 75 to 150° C. by a straight line, followed byextrapolation, was used. However, as for a curve in which acrystallization peak or bending by a glass transition point was judgedto appear in the range of 75 to 150° C., the curve was approximated by astraight line in a range excluding this range, whereby this line wasdetermined as a base line. The range of integration was set to be in arange of ±20° C. from the peak top position of each peak, a range from aposition where the absolute value of the (Heat flow value—base linevalue at each temperature) becomes smallest on the low-temperature sidefrom the peak top to a position where the absolute value of the (Heatflow value—base line value at each temperature) becomes smallest on thehigh-temperature side from the peak top. In this range, the integratedintensity was calculated by means of the analysis software.

The peak positions Tc1 and Tc2 and the peak integrated intensities Hc1,Hc2, Hc1p and Hc2p were obtained.

The ionic conductivity (σ) measured after the heat treatment is shown inTable 1.

The ionic conductivity was measured as follows.

Ionic Conductivity (σ)

A powder sample of solid electrolyte glass was formed to a shape havinga cross-section surface with a diameter of 10 mm (cross-section areaS=0.785 cm²), and a height (L) of 0.1 to 0.3 cm. After that, a heattreatment was conducted to allow the sample to be glass ceramic.

Electrode terminals were attached to the upper and bottom side of thesample piece obtained, respectively, and a measurement was conducted bythe alternating current impedance method (frequency range: 5 MHz to 0.5Hz, amplitude: 10 mV) to obtain a Cole-Cole plot. The real part Z′ (Ω)at the point where —Z″ (Ω) was the smallest near the right end of acircular arc observed in the higher-frequency region was set to the bulkresistance R (Ω) of an electrolyte. With the bulk resistance, accordingto the following formula, the ionic conductivity σ (S/cm) wascalculated.

R=ρ(L/S)

σ=1/p

The measurement was conducted with the distance of a lead being about 60cm.

Comparative Example 1 Raw Material Ratio:Li₂S/P₂S₅/LiBr=67/33/17.3):MMMethod

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 1, except thatthe raw materials were changed to 0.264 g (0.0056 mol) of lithiumsulfide, 0.616 g (0.00276 mol) of phosphorus pentasulfide (manufacturedby Sigma-Aldrich Co.), and 0.127 g (0.00145 mol) of lithium bromide(manufactured by Sigma-Aldrich Co.) and the heat treatment temperaturefor allowing the glass to be glass ceramic was changed to 270° C. Theresults are shown in Table 1.

The results of the differential thermal analysis of the solidelectrolyte glass are shown in FIG. 2. As shown in FIG. 2, the solidelectrolyte glass of Comparative Example 1 has two peaks. However, thetwo peaks are overlapped one on another, and hence, a region that has avalue of 20% or less of the maximum value (height) of each peak is notpresent between the two peaks. Accordingly, the solid electrolyte glassof Comparative Example 1 does not have “two exothermic peaks that areseparated from each other”.

Example 2 Raw Material Ratio:Li₂S/P₂S₅/LiBr=77/23/17.3):MM Method

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 1, except thatthe raw materials were changed to 0.349 g (0.0076 mol) of lithiumsulfide, 0.503 g (0.00227 mol) of phosphorus pentasulfide (manufacturedby Sigma-Aldrich Co.), and 0.148 g (0.00171 mol) of lithium bromide(manufactured by Sigma-Aldrich Co.) and the heat treatment temperaturefor allowing the glass to be glass ceramic was changed to 220° C. Theresults are shown in Table 1.

The results of the differential thermal analysis of the solidelectrolyte glass are shown in FIG. 2.

Example 3 Raw Material Ratio:Li₂S/P₂S₅/LiBr=80/20/17.9):MM Method

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 1, except thatthe raw materials were changed to 0.384 g (0.0083 mol) of lithiumsulfide, 0.460 g (0.00207 mol) of phosphorus pentasulfide (manufacturedby Sigma-Aldrich Co.), and 0.162 g (0.00187 mol) of lithium bromide(manufactured by Sigma-Aldrich Co.) and the heat treatment temperaturefor allowing the glass to be glass ceramic was changed to 220° C. Theresults of the solid electrolyte glass are shown in Table 1.

The results of the differential thermal analysis are shown in FIG. 2.

Comparative Example 2 Raw Material Ratio:Li₂S/P₂S₅/LiBr=83/16/18.7):MMMethod

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 1, except thatthe raw materials were changed to 0.422 g (0.0091 mol) of lithiumsulfide, 0.405 g (0.00182 mol) of phosphorus pentasulfide (manufacturedby Sigma-Aldrich Co.), and 0.178 g (0.00205 mol) of lithium bromide(manufactured by Sigma-Aldrich Co.) and the heat treatment temperaturefor allowing the glass to be glass ceramic was changed to 180° C. Theresults are shown in Table 1.

The results of the differential thermal analysis of the solidelectrolyte glass are shown in FIG. 2. As shown in FIG. 2, the solidelectrolyte glass of Comparative Example 2 has two peaks. However, thetwo peaks are overlapped one on another, and hence, a region that has avalue of 20% or less of the maximum value (height) of each peak is notpresent between the two peaks. Accordingly, the solid electrolyte glassof Comparative Example 1 does not have “two exothermic peaks that areseparated from each other”.

The reason therefor is assumed to be as follows. Comparing Example 3with Comparative Example 2, when Li₂S and P₂S₅ and LiBr were used as rawmaterials, the ratio of Li₂S was higher than Li₂S/P₂S₅=80/20;specifically, Li₂S/P₂S₅=83/16. Therefore, the solid electrolyte glass ofComparative Example 2 did not have the “two exothermic peaks that areseparated from each other”.

Comparative Example 3 Raw Material Ratio:Li₂S/P₂S₅/LiBr=86/14/19.0):MMMethod

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 1, except thatthe raw materials were changed to 0.453 g (0.0098 mol) of lithiumsulfide, 0.362 g (0.00163 mol) of phosphorus pentasulfide (manufacturedby Sigma-Aldrich Co.), and 0.191 g (0.00220 mol) of lithium bromide(manufactured by Sigma-Aldrich Co.) and the heat treatment temperaturefor allowing the glass to be glass ceramic was changed to 190° C. Theresults are shown in Table 1.

The results of the differential thermal analysis of the solidelectrolyte glass are shown in FIG. 2.

Example 4 Raw Material Ratio:Li₂S/P₂S₅/PBr₃=80/20/5):MM Method

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 1, except thatthe raw materials were changed to 0.397 g (0.00844 mol) of lithiumsulfide, 0.467 g (0.00210 mol) of phosphorus pentasulfide (manufacturedby Sigma-Aldrich Co.), and 0.147 g (0.00053 mol) of lithium bromide andthe heat treatment temperature for allowing the glass to be glassceramic was changed to 240° C. The results are shown in Table 1.

As compared with Example 1, the second peak was shifted to thehigh-temperature side, and as a result, ΔT was widened.

Example 5 Raw Material Ratio:Li₂S/P₂S₅/LiBr=75/25/16.8):MM Method (1)Synthesis of Solid Electrolyte Glass

0.337 g (0.00717 mol) of lithium sulfide produced in Production Example1 and 0.532 g (0.00239 mol) of phosphorus pentasulfide (manufactured bySigma-Aldrich Co.) were mixed, and the mixture was subjected tomechanical milling by a ball mill in the same manner as in Example 1 toobtain sulfide glass (precursor).

To the obtained precursor, 0.140 g (0.00161 mol) of lithium bromide(manufactured by Sigma-Aldrich Co.) was added, and mixed sufficiently.Further, the mixture was subjected to mechanical milling under the sameconditions as those mentioned above (rotation number: 370 rpm, for 20hours) to obtain a solid electrolyte glass.

The evaluation was conducted in the same manner as in Example 1, and theresults are shown in Table 1. In this solid electrolyte glass, the firstpeak temperature was lowered, and as a result, ΔT was widened ascompared with Example 1.

(2) Synthesis of Solid Electrolyte Glass Ceramic

The obtained solid electrolyte glass was subjected to a heat treatmentat a temperature (220° C.) for 2 hours between the two exothermic peaksin an argon atmosphere.

In the same manner as in Example 1, the solid electrolyte glass ceramicwas evaluated. The results are shown in Table 1.

Example 6 Raw Material Ratio:Li₂S/P₂S₅/LiI=75/25/16.8):MM Method

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 5, except thatthe raw materials were changed to 0.316 g (0.0067 mol) of lithiumsulfide, 0.494 g (0.00222 mol) of phosphorus pentasulfide (manufacturedby Sigma-Aldrich Co.), and 0.200 (0.00149 mol) of LiI and the heattreatment temperature for allowing the glass to be glass ceramic waschanged to 210° C. The results are shown in Table 1.

Example 7 Raw Material Ratio:Li₂S/P₂S₅/PI3=80/20/5):MM Method

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 4, except thatthe raw materials were changed to 0.396 g (0.0078 mol) of lithiumsulfide, 0.434 (0.00195 mol) of phosphorus pentasulfide (manufactured bySigma-Aldrich Co.), and 0.417 (0.00050 mol) of PI3. The results areshown in Table 1.

Example 8 Raw Material Ratio:Li₂S/P₂S₅/LiBr=75/25/16.8):MM Method

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced in the same manner as in Example 1, except that the charging inthe mill pot was conducted in a dry air having a dew point −40° C. orlower. The oxygen concentration at this time was about 20%. The resultsare shown in Table 1. As compared with Example 1, the first peak wasshifted to the low-temperature side.

Example 9 Raw Material Ratio:Li₂S/P₂S₅/LiBr=75/25/16.8):Slurry Method(1) Synthesis of Solid Electrolyte Glass

An apparatus shown in FIG. 3 was used. A production apparatus 1 isprovided with a beads mill 10 that allows raw materials to be reactedwhile pulverizing, and a reaction tank 20 that allows the raw materialsto react. The reaction tank 20 is formed of a container 22 and astirring blade 24. The stirring blade 24 is driven by a motor (M).

The beads mill 10 is provided with a heater 30 that can pass hot wateraround the mill 10. The reaction tank 20 is placed in an oil bath 40.The oil bath 40 heats the raw materials and the solvent in the container22 to a prescribed temperature. The reaction tank 20 is provided with acooling tube 26 that cools and liquefies the evaporated solvent.

The beads mill 10 and the reaction tank 20 are connected by a firstconnection tube 50 and a second connection tube 52. The first connectiontube 50 moves the raw materials and the solvent in the beads mill 10 tothe reaction tank 20, and the second connection tube 52 moves the rawmaterials and the solvent in the reaction tank 20 to the beads mill 10.In order to allow the raw materials or the like to circulate through theconnection tubes 50 and 52, a pump 54 (a diaphragm pump, for example) isprovided in the second connection tube 52.

As the beads mill 10, a Star Mill Miniature (0.15 L) (beads mill)(manufactured by Ashizawa Finetech Ltd.) was used, and 444 g of zirconiaballs each having a diameter of 0.5 mm were put in the mill. As thereaction tank 20, a 1.5 L-glass-made reaction apparatus provided with astirring blade was used. As the temperature-retaining tank, a 1.5L-glass-made reaction apparatus provided with a stirring blade was used.

As for all of the equipment used, those from which water had beenremoved in advance by a dryer was used. Further, the water content inthe dehydrated toluene was found to be 8.4 ppm by the Karl Fischermethod.

A mixture obtained by adding 1248 ml (water content 8.4 ppm) ofdehydrated toluene (manufactured by Wako Pure Chemical Industries, Ltd.)to 33.7 g (64 mol %) of lithium sulfide in Production Example 1, 53.2 g(21 mol %) of P₂S₅ (manufactured by Sigma-Aldrich Co.) and 14.1 g (15mol %) of LiBr (manufactured by Sigma-Aldrich Co.) was charged in thetemperature-retaining tank and the mill. The charging of the rawmaterials and the recovery of the product were conducted in a dry air ata dew point −40° C. or lower.

By means of the pump, the content was allowed to circulate between thetemperature-retaining tank and the mill at a flow rate of 480 mL/min,and the temperature-retaining tank was heated to 80° C.

A hot water was passed through the mill main body by externalcirculation such that the liquid temperature could be kept at 70° C.,and the mill main body was operated at a circumferential speed of 12m/s.

The resulting slurry was filtrated and dried in the air, and then driedat 160° C. for 2 hours by a tube heater. As a result, a solidelectrolyte glass was obtained as powder. The recovery at this time was95% and no adhered matters were observed in the reaction apparatus. Theresults of evaluation are shown in Table 1.

(2) Synthesis of Solid Electrolyte Glass Ceramic

The resulting solid electrolyte glass was put in an argon atmosphere,and was subjected to a heat treatment for 2 hours at a temperature (210°C.) between the two exothermic peaks.

The solid electrolyte glass ceramic was evaluated in the same manner asin Example 1. The results are shown in Table 1.

Example 10 Raw Material Ratio:Li₂S/P₂S₅/LiBr=74.4/25.6/17.3):MM Method

The solid electrolyte glass and the solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 1, except thatthe raw materials were changed to 0.329 g (0.0070 mol) of lithiumsulfide, 0.537 g (0.00241 mol) of phosphorus pentasulfide (manufacturedby Sigma-Aldrich Co.) and 0.144 (0.00164 mol) of lithium bromide and theheat treatment temperature for allowing the glass to be glass ceramicwas changed to 220° C. The results are shown in Table 1.

Example 11 Raw MaterialRatio:Li₂S/P₂S₅/LiBr/Li₂SO₃=74.4/25.6/17.3/1.2):MM Method

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 1, except that 1wt % of Li₂SO₃ (0.0101 g, 0.00011 mol) was further added, and the heattreatment temperature for allowing the glass to be glass ceramic waschanged to 220° C. The results are shown in Table 1. Li₂SO₃ was dried invacuum in advance.

Example 12 Raw Material Ratio:Li₂S/P₂S₅/LiBr/Li₂SO₃=74.4/25.6/17.3/2):MMMethod

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 11, except that2 wt % of Li₂SO₃ (0.020 g, 0.00021 mol) was further added. The resultsare shown in Table 1.

Example 13 Raw Material Ratio:Li₂S/P₂S₅/LiBr/Li₂SO₃=74.4/25.6/17.3/5):MMMethod

A solid electrolyte glass and a solid electrolyte glass ceramic wereproduced and evaluated in the same manner as in Example 11, except that5 wt % of Li₂SO₃ (0.050 g, 0.00053 mol) was further added. The resultsare shown in Table 1.

Comparative Example 4

A solid electrolyte glass ceramic was produced and evaluated in the samemanner as in Example 1, except that the solid electrolyte glass obtainedin Example 1 was subjected to a heat treatment at 200° C. for 2 hours.The results are shown in Table 1.

Comparative Example 5

A solid electrolyte glass ceramic was produced and evaluated in the samemanner as in Example 1, except that the solid electrolyte glass obtainedin Example 1 was subjected to a heat treatment at 300° C. for 2 hours.The results are shown in Table 1.

Example 14

A solid electrolyte glass ceramic was produced and evaluated in the samemanner as in Example 1, except that the solid electrolyte glass obtainedin Example 1 was subjected to a heat treatment at 250° C. for 2 hours.The results are shown in Table 1.

TABLE 1 Heat treatment tem- Tc1 Tc2 ΔT perature Hc1/ Hc2/ σ (° C.) (°C.) (° C.) (° C.) Hc1p Hc2p (mS/cm) Example 1 210 267 57 230 0 1.1 2.1Comp. Ex. 1 268 287 19 270 0 1.0 0.04 Example 2 206 251 45 220 0 0.981.2 Example 3 200 246 46 220 0 0.90 0.80 Comp. Ex. 2 175 185 10 180 00.05 0.34 Comp. Ex. 3 187 None — 190 0 0 0.41 Example 4 220 287 67 240 01.01 1.6 Example 5 192 263 72 220 0 0.98 1.0 Example 6 189 305 116  2100 1.15 1.7 Example 7 206 312 106  240 0 1.0 1.0 Example 8 201 265 64 2100 1.02 2.0 Example 9 201 265 64 210 0 1.05 2.2 Example 10 210 257 47 2200 0.98 1.6 Example 11 208 266 58 220 0 0.10 1.4 Example 12 207 272 65220 0 0.95 1.5 Example 13 203 265 62 220 0 0.88 0.9 Comp. Ex. 4 — — —200 95 0.98 0.6 Comp. Ex. 5 — — — 300 0 0 0.08 Example 14 — — — 250 00.79 2.0 Tc1: Peak temperature of the exothermic peak on thelow-temperature side Tc2: Peak temperature of the exothermic peak on thehigh-temperature side ΔT: Temperature difference between peaks (Tc2 −Tc1) Hc1: Integrated intensity of the first peak after the heattreatment Hc2: Integrated intensity of the second peak after the heattreatment Hc1p: Integrated intensity of the first peak before the heattreatment Hc2p: Integrated intensity of the second peak before the heattreatment σ: Ionic conductivity

The solid ³¹PNMR spectrum and the crystallization degree x_(c) of thesolid electrolyte produced in Examples and Comparative Examples weremeasured by the following method.

(1) Solid ³¹PNMR Spectrum

Apparatus: JNM-CMXP302NMR manufactured by JEOL Ltd.

Observed nucleus: ³¹P

Observed frequency: 121.339 MHz

Measurement temperature: room temperature

Measurement method: MAS method

Pulse sequence: single pulse

90° pulse width: 4 μs

Magic Angle Spinning: 8600 Hz

Waiting time until next application of pulse after FID measurement: 100to 2000 s (set so as to be 5 or more times as long as the maximumspin-lattice relaxation time)

Number of integration: 64

The chemical shift was determined by using (NH₄)₂HPO₄ (chemical shift1.33 ppm) as the external standard.

In order to prevent denaturing by moisture in the air at the time ofcharging the sample, the sample was charged in a sealable sample tube ina dry box in which dry nitrogen was continuously flown.

(2) Crystallization Degree x_(c)

For the solid ³¹PNMR spectrum obtained by measuring the sample under theconditions (1), a resonance line observed at 70 to 120 ppm was separatedto Gaussian curves using the non-linear least-squares method tocalculate the crystallization degree from the area ratio of each of thecurves. Hereinbelow, a specific explanation will be made on the methodfor calculating the crystallization degree x_(c) taking the solid ³¹PNMRspectrum as an example. The peak position is a position after the waveseparation.

The resonance line (FIG. 4) observed at 70 to 120 ppm of the solid³¹PNMR is separated into 7 Gaussian curves shown in Table 2 using thenon-linear-squares method (FIG. 5). The resonance line is not alwaysseparated into 7 Gaussian curves, and if a structure indicated by theassignment was not present in the sample, the Gaussian curvecorresponding to this assignment cannot be observed.

TABLE 2 Peak position No. (ppm) Line width (Hz) Belonging 1 106.6 ± 0.5 800 to 2000 P₂S₆ ⁴⁻ (glass) 2 92.5 ± 0.6 500 to 1000 Metastable phase(Crystal) 3 87.4 ± 0.6 500 to 1500 Metastable phase (Crystal) 4 86.4 ±0.5 10 to 500 PS₄ ³⁻ (Crystal) 5 76.9 ± 0.5 500 to 1000 Metastable phase(Crystal) 6 83.5 ± 0.5 500 to 1500 PS₄ ³⁻ (Glass) 7 91.0 ± 0.6 800 to1500 P₂S₇ ⁴⁻ (Glass)

The ratio x_(c) (mol %) of the crystals that give peaks 2, 3 and 5 whichappear when a heat treatment was conducted at a temperature between thetwo exothermic peaks was calculated by the following formula. The arearatios of peaks 1 to 7 are respectively taken as I₁ to I₇.

x _(c)=100×(I ₂ +I ₃ +I ₅)/(I ₁ +I ₂ +I ₃ +I ₄ +I ₅ +I ₆ +I ₇)

Example 15

As the stirrer, a Star Mill Miniature (0.15 L) (beads mill)(manufactured by Ashizawa Finetech Ltd.) was used, and 444 g of zirconiaballs each having a diameter of 0.5 mm were put in the mill. As thetemperature-retaining tank, a 1.5 L-glass-made reaction apparatusprovided with a stirring blade was used.

The weighing, addition and sealing mentioned above were conducted in dryair. As for the all of the equipment used, those from which water hadbeen removed in advance by a dryer were used. Further, the water contentin the dehydrated toluene was found to be 8.4 ppm by the Karl Fischermethod.

A mixture obtained by adding to 33.7 g (0.64 mol %) of lithium sulfidein Production Example 1, 53.2 g (0.21 mol %) of P₂S₅ (manufactured bySigma-Aldrich Co.) and 14.1 g (0.15 mol) of LiBr (manufactured bySigma-Aldrich Co.), 1248 ml (water content 8.4 ppm) of dehydratedtoluene (manufactured by Wako Pure Chemical Industries, Ltd.) wascharged in the temperature-retaining tank and the mill.

By means of a pump, the content was allowed to circulate between thetemperature-retaining tank and the mill at a flow rate of 480 mL/min,and the temperature-retaining tank was heated to 80° C. A hot water waspassed through the mill main body by external circulation such that theliquid temperature could be kept at 70° C., and the mill main body wasoperated at a circumferential speed of 12 m/s. A slurry was collected atevery two hours, the slurry was dried at 150° C., whereby white yellowpowder slurry (creamy slurry) was obtained.

The resulting slurry was filtrated and dried in the air, and then driedat 160° C. for 2 hours by a tube heater. As a result, a solidelectrolyte was obtained as powder. The recovery at this time was 95%and no adhered matters were observed in the reaction apparatus.

As a result of analysis of the resulting electrolyte by the differentialthermal analysis measurement, an exothermic peak ascribable tocrystallization was observed at 201° C. (Tc1) and 265° C. (Tc2).

The resulting sulfide glass was subjected to a heat treatment at 201° C.for 2 hours to allow it to be glass ceramic, whereby a solid electrolytewas produced. The ionic conductivity of this solid electrolyte wasmeasured by the AC impedance method (measurement frequency: 100 Hz to 15MHz). It was found to be 1.9×10⁻³ S/cm.

The ionic conductivity, the crystallization degree x_(c) and presence orabsence of peak 2 (92.5±0.5 ppm), peak 3 (87.4±0.5 ppm) and peak 5(76.9±0.5 ppm) of the solid electrolyte produced in Example 15 and thefollowing Examples and Comparative Examples are shown in Table 3.

Example 16

The solid electrolyte was produced and evaluated in the same manner asin Example 15, except that the heat treatment temperature of the sulfideglass was changed to 210° C. (2 hours). This solid electrolyte had anionic conductivity of 2.2×10⁻³ S/cm.

Example 17

The solid electrolyte was produced and evaluated in the same manner asin Example 15, except that the heat treatment temperature of the sulfideglass was changed to 220° C. (2 hours). This solid electrolyte had anionic conductivity of 1.8×10⁻³ S/cm.

Example 18

The solid electrolyte was produced and evaluated in the same manner asin Example 15, except that the heat treatment temperature of the sulfideglass was changed to 230° C. (2 hours). This solid electrolyte had anionic conductivity of 1.3×10⁻³ S/cm.

Comparative Example 6

In Example 15, evaluation was conducted for the solid electrolyte forwhich no heat treatment was conducted for the sulfide glass. The ionicconductivity of this sulfide glass was 4.2×10⁻⁴ S/cm.

Comparative Example 7

A solid electrolyte was produced and evaluated in the same manner as inExample 15, except that the heat treatment temperature of the sulfideglass was changed to 300° C. (2 hours). The ionic conductivity of thissulfide glass was 2.3×10⁻⁵ S/cm.

TABLE 3 Heat treatment Presence or absence of peak temperature Ionicconductivity x_(c) 92.5 ± 0.6 87.4 ± 0.6 76.9 ± 0.5 (° C.) (S/cm) (mol%) (ppm) (ppm) (ppm) Example 15 201 1.9 × 10⁻³ 93.2 ∘ ∘ ∘ Example 16 2102.2 × 10⁻³ 95.0 ∘ ∘ ∘ Example 17 220 1.8 × 10⁻³ 93.5 ∘ ∘ ∘ Example 18230 1.3 × 10⁻³ 85.0 ∘ ∘ ∘ Comp. Ex. 6 — 4.2 × 10⁻⁴ 0 x x x Comp. Ex. 7300 2.3 × 10⁻⁵ 0 x x x

INDUSTRIAL APPLICABILITY

The solid electrolyte glass and the solid electrolyte ceramic of theinvention are preferable as members of an all-solid battery such as apositive electrode layer, a solid electrolyte layer, a negativeelectrode or the like.

The all-solid battery of the invention can be used as a battery of PDA,a portable electronic device, a home-use compact power storage facility,an auto-bicycle powered by a motor, an electric vehicle, a hybridelectric vehicle or the like.

Although only some exemplary embodiments and/or examples of thisinvention have been described in detail above, those skilled in the artwill readily appreciate that many modifications are possible in theexemplary embodiments and/or examples without materially departing fromthe novel teachings and advantages of this invention. Accordingly, allsuch modifications are intended to be included within the scope of thisinvention.

The document of the Japanese application specification claiming priorityunder the Paris Convention are incorporated herein by reference in itsentirety.

1. A solid electrolyte glass at least comprising: at least one alkalimetal element; a phosphorus (P) element; a sulfur (S) element; and oneor more halogen elements selected from I, Cl, Br and F; wherein thesolid electrolyte glass has two exothermic peaks that are separated fromeach other in a temperature range of 150° C. to 350° C. as determined bydifferential scanning calorimetric measurement (in a dry nitrogenatmosphere at a temperature-elevating speed of 10° C./min from 20 to600° C.).
 2. The solid electrolyte glass according to claim 1, whereinthe difference in temperature between the peak top positions of the twoexothermic peaks is 20° C. or higher and 150° C. or lower.
 3. The solidelectrolyte glass according to claim 1, wherein the difference intemperature between the peak top positions of the two exothermic peaksis 30° C. or higher and 130° C. or lower.
 4. The solid electrolyte glassaccording to claim 1, that has a composition represented by thefollowing formula (1):L_(a)M_(b)P_(c)S_(d)X_(e)  (1) wherein in the formula L is an alkalimetal; M is one or more elements selected from B, Al, Si, Ge, As, Se,Sn, Sb, Te, Pb and Bi; and X is one or more halogen elements selectedfrom I, Cl, Br and F; and a to e independently satisfy the followingformula:0<a≦12, 0≦b≦0.2, c=1, 0<d≦9 and 0<e≦9.
 5. A method for producing thesolid electrolyte glass according to claim 1, wherein the following(1-A), (1-B) and (1-C) are used as raw materials: (1-A) alkali metalsulfide (1-B) compound represented by M′_(m)S_(n) (1-C) compoundrepresented by M″_(w)X_(y) wherein in the formula M′ is B, Al, Si, P orGe; M″ is Li, Na, B, Al, Si, P, S, Ge, As, Se, Sn, Sb, Te, Pb or Bi; Xis F, Cl, Br or I; w is an integer of 1 to 2; and m, n and y are aninteger of 1 to
 10. 6. The method for producing a solid electrolyteglass according to claim 5, comprising a step of reacting the rawmaterials (1-A) and (1-B), and adding the raw material (1-C) to allow itto react with a reaction product of the raw materials (1-A) and (1-B).7. The method for producing a solid electrolyte glass according to claim5, comprising a step of reacting in an atmosphere having an oxygenconcentration of 19 to 21%.
 8. The method for producing a solidelectrolyte glass according to claim 5, wherein 1 to 5 mol % of Li₂SO₃is further added as a component (1-D).
 9. A solid electrolyte glass thatis obtained by the method for producing a solid electrolyte glassaccording to claim
 5. 10. A solid electrolyte glass ceramic obtained bysubjecting the solid electrolyte glass according to claim 1 to a heattreatment at a temperature between the two exothermic peaks.
 11. Thesolid electrolyte glass ceramic according to claim 10 that has an ionicconductivity of 1×10⁻³ S/cm or more.
 12. A positive electrode mix thatcomprises at least one of the solid electrolyte glass according to claim1, and a positive electrode active material.
 13. A negative electrodemix that comprises at least one of the solid electrolyte glass accordingto claim 1, and a negative electrode active material.
 14. An all-solidbattery that is provided with a solid electrolyte layer containing atleast one of the solid electrolyte glass according to claim
 1. 15. Anall-solid battery provided with a positive electrode layer comprisingthe positive electrode mix according to claim
 12. 16. An all-solidbattery provided with a negative electrode layer comprising the negativeelectrode mix according to claim
 13. 17. The all-solid battery accordingto claim 14 that is obtained by heat treating the solid electrolyteglass contained in the solid electrolyte layer, the positive electrodemix or the negative electrode mix at a temperature between exothermicpeak temperatures of the two exothermic peaks that are separated fromeach other in a temperature range of 150° C. to 350° C. as determined bydifferential scanning calorimetric measurement (in a dry nitrogenatmosphere at a temperature-elevating speed of 10° C./min and from 20 to600° C.).